Here are three rules to live by when programming in C++ and C# (or other languages with similar syntax!):
1) Semicolons are the work of the devil. Make sure you check for semicolons often. They can lead to some strange errors.
2) Braces are evil incarnate. Make sure you have matching braces. Make sure they are in the right spot. These can lead to even stranger errors.
3) Spelling and Case. Worst offender in this list. A pain in the ass to figure out sometimes.
If you check your code often for these three things, you will eliminate a ton of errors in your code. I figure that over 90% of errors can be resolved with one of these three rules, especially with newer programmers.